Background Shenling Baizhu Powder (SBP) is a traditional Chinese medicine (TCM) prescription, which has the good efficacy on gastrointestinal toxicity. In this study, we used gut microbiota analysis, metabonomics and network pharmacology to investigate the therapeutic effect of SBP on pyrotinib-induced diarrhea. Methods 24 Rats were randomly divided into 4 groups: control group, SBP group (3.6 g/kg /bid SBP for 10 days), pyrotinib model group (80 mg/kg/qd pyrotinib) and pyrotinib + SBP treatment group. A 16S rRNA sequencing was used to detect the microbiome of rat fecal bowel. Metabolic profiles were collected by non-targeted metabolomics and key metabolic pathways were identified using MetaboAnalyst 5.0. The antitumor effect of SBP on cells treated with pyrotinib was measured using a CCK-8 assay. Network pharmacology was used to predict the target and action pathway of SBP in treating pyrotinib-related diarrhea. Results In vivo study indicated that SBP could significantly alleviate pyrotinib-induced diarrhea, reaching a therapeutic effect of 66.7%. SBP could regulate pyrotinib-induced microbiota disorder. LEfSe research revealed that the SBP could potentially decrease the relative abundance of Escherichia, Helicobacter and Enterobacteriaceae and increase the relative abundance of Lachnospiraceae, Bacilli, Lactobacillales etc. In addition, 25-Hydroxycholesterol, Guanidinosuccinic acid, 5-Hydroxyindolepyruvate and cAMP were selected as potential biomarkers of SBP for pyrotinib-induced diarrhea. Moreover, Spearman's analysis showed a correlation between gut microbiota and metabolite: the decreased 25-hydroxycholesterol in the pyrotinib + SBP treatment group was negatively correlated with Lachnospiraceae while positively correlated with Escherichia and Helicobacter. Meanwhile, SBP did not affect the inhibitory effect of pyrotinib on BT-474 cells and Calu-3 cells in vitro. Also, the network analysis further revealed that SBP treated pyrotinib-induced diarrhea through multiple pathways, including inflammatory bowel disease, IL-17 signaling pathway, pathogenic Escherichia coli infection and cAMP signaling pathway. Conclusions SBP could effectively relieve pyrotinib-induced diarrhea, revealing that intestinal flora and its metabolites may be involved in this process.

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Ubiquitin-specific-processing proteases 35 (USP35) is an under-characterized deubiquitinase and its role in colorectal cancer (CRC) remains unclear. Here, we focus on delineating the impact of USP35 on CRC cell proliferation and chemo-resistance, as well as the possible regulatory mechanism. By examining the genomic database and clinical samples, we found that USP35 was overexpressed in CRC. Further functional studies showed that enhanced USP35 expression promoted CRC cell proliferation and resistance to oxaliplatin (OXA) and 5-fluorouracil (5-FU), whereas USP35 depletion impeded cell proliferation and sensitized cells to OXA and 5-FU treatments. Then, to explore the possible mechanism underlying USP35-triggered cellular responses, we performed co-immunoprecipitation (co-IP) followed by mass spectrometry (MS) analysis and identified α-L-fucosidase 1 (FUCA1) as a direct deubiquitiation target of USP35. Importantly, we demonstrated that FUCA1 was an essential mediator for USP35-induced cell proliferation and chemo-resistance in vitro and in vivo. Finally, we observed that nucleotide excision repair (NER) components (e.g., XPC, XPA, ERCC1) were up-regulated by USP35-FUCA1 axis, indicating a potential mechanism for USP35-FUCA1-mediated platinum resistance in CRC. Together, our results for the first time explored the role and important mechanism of USP35 in CRC cell proliferation and chemotherapeutic response, providing a rationale for USP35-FUCA1-targeted therapy in CRC.